BAC Trillium Series - Modes of Operation

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Warm Air Out
Air in at
Dry-Bulb
Temp
Air in at
Dry-Bulb
Temp
Air
Cooled
to 2-3ºF
of Wet-
Bulb
Temp
Air
Cooled
to 2-3ºF
of Wet-
Bulb
Temp
Water
Distribution
System
Water
Distribution
System
Pump
Liquid Out
Microchannel
Coils
Liquid Out
Vapor In
Vapor In
Pre-Cooler
Media
Pre-Cooler
Media
[1]
[1] [1]
[1]
NOTE: For transcritical CO
2
operation, the coil operates
with vapor in and vapor out. For
subcritical CO
2
operation, the coil
operates with subcritical vapor in
and liquid out.
Figure 22. Pre-Cooler Mode Operation
Warm Air Out
Air in at
Dry-Bulb
Temp
Air in at
Dry-Bulb
Temp
Liquid Out
Pre-Cooler
Pads
Microchannel
Coils
Liquid Out
Vapor In
Vapor In
Pre-Cooler
Pads
[1]
[1] [1]
[1]
Figure 21. Dry Mode Operation
Modes of Operation
TrilliumSeries™ Adiabatic Products will operate in two basic modes: Dry Mode and Pre-Cooler
Mode. In Dry Mode, the water pump will be off and the unit will operate as an air-cooled
condenser or fluid cooler. During Pre-Cooler Mode, the unit will use a pump to deliver water
over the Pre-Cooler Pads, making the unit operate as an adiabatic condenser or fluid cooler.
Dry Mode
When the ambient air is below the set point, the unit runs as a dry cooler to save water and
energy. The ambient air condenses the refrigerant or cools the process fluid in the coils which
is then returned to the system.
Pre-Cooler Mode
When the unit is in Pre-Cooler Mode to manage the water: maximizing Pre-Cooler Pad
wetting in Pre-Cooler mode and the ambient air reaches a pre-set temperature, water is
evenly sprayed over the highly efficient Pre-Cooler Pads. The air is humidified as it passes
through the media, cooling down to 2-3ºF above the wet-bulb temperature. Such substantial
depression of the dry bulb temperature results in a major increase in dry cooling capacity.
The cooler air passes over the coil and condenses the refrigerant or cools the process fluid in
the coil which is then returned to the system. In the sump there is an industrial-duty pump
that supplies the water. Part of the distributed water is evaporated while the excess water
assists in rinsing the pads. The EcoFlex Controls determine when the water is purged from
the sump.